Electrically driven proton transfer promotes Brønsted acid catalysis by orders of magnitude

Science, Journal Year: 2024, Volume and Issue: 383(6684), P. 757 - 763

Published: Feb. 15, 2024

Electric fields play a key role in enzymatic catalysis and can enhance reaction rates by 100,000-fold, but the same rate enhancements have yet to be achieved thermochemical heterogeneous catalysis. In this work, we probe influence of catalyst potential interfacial electric on Brønsted acid We observed that variations applied ~380 mV led 100,000-fold enhancement for 1-methylcyclopentanol dehydration, which was catalyzed carbon-supported phosphotungstic acid. Mechanistic studies support model electrostatic drop drives quasi-equilibrated proton transfer adsorbed substrate prior rate-limiting C-O bond cleavage. Large increases with were also Ti/TiO

Language: Английский

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Oxidation of interfacial cobalt controls the pH dependence of the oxygen evolution reaction

Nature Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 28, 2025

Transition metal oxides often undergo dynamic surface reconstruction under oxygen evolution reaction conditions to form the active state, which differs in response electrolyte pH. The resulting pH dependency of catalytic activity is commonly observed but poorly understood. Herein we track Co oxidation state changes at different pH-directed (hydr)oxide/electrolyte interfaces using operando X-ray absorption spectroscopy characterizations. Combined with situ electrochemical analyses, establish correlations between redox dynamics, flat band potential and explain activity. Alkaline environments provide a low that yields low-potential transformation, favours reconstruction. Neutral acidic afford an anodic shift transformation increases overpotential. larger overpotential neutral attributable poor atom polarizability slow changes. These findings reveal interfacial directly determine

Language: Английский

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Transition from Sequential to Concerted Proton-Coupled Electron Transfer of Water Oxidation on Semiconductor Photoanodes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(43), P. 23849 - 23858

Published: Oct. 20, 2023

Accelerating proton transfer has been demonstrated as key to boosting water oxidation on semiconductor photoanodes. Herein, we study proton-coupled electron (PCET) of five typical photoanodes [i.e., α-Fe2O3, BiVO4, TiO2, plasmonic Au/TiO2, and nickel-iron oxyhydroxide (Ni1-xFexOOH)-modified silicon (Si)] by combining the rate law analysis H2O molecules with H/D kinetic isotope effect (KIE) operando spectroscopic studies. An unexpected universal half-order kinetics is observed for H2O, referring a sequential proton-electron pathway, which rate-limiting factor that causes sluggish performance. Surface modification Ni1-xFexOOH electrocatalyst break this limitation exhibits normal first-order accompanied much enhanced KIE values, facilitating turnover frequency 1 order magnitude. It first time found be PCET modulator. The illustrates an effective strategy modulating surfaces.

Language: Английский

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Unraveling a Concerted Proton-Coupled Electron Transfer Pathway in Atomically Precise Gold Nanoclusters

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(12), P. 8706 - 8715

Published: March 15, 2024

Metal nanoclusters (MNCs) represent a promising class of materials for catalytic carbon dioxide and proton reduction as well dihydrogen oxidation. In such reactions, multiple proton-coupled electron transfer (PCET) processes are typically involved, the current understanding PCET mechanisms in MNCs has primarily focused on sequential mode. However, concerted pathway, i.e., electron–proton (CEPT), despite its potential higher rate lower reaction barrier, still lacks comprehensive elucidation. Herein, we introduce an experimental paradigm to test feasibility CEPT process MNCs, by employing Au18(SR)14 (SR denotes thiolate ligand), Au22(SR)18, Au25(SR)18– model clusters. Detailed investigations indicate that photoinduced reactions designed system proceed via pathway. Furthermore, constants gold (AuNCs) have been found be correlated with both size cluster flexibility Au–S framework. This newly identified behavior AuNCs is prominently different from observed semiconductor quantum dots plasmonic metal nanoparticles. Our findings crucial importance unveiling quantum-confined nanomaterials future rational design more efficient catalysts.

Language: Английский

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Insight of proton transport phenomena in semiconductor ionic materials

Journal of Power Sources, Journal Year: 2024, Volume and Issue: 598, P. 234148 - 234148

Published: Feb. 15, 2024

Language: Английский

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Direct Evidence for a Sequential Electron Transfer–Proton Transfer Mechanism in the PCET Reduction of a Metal Hydroxide Catalyst

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(3), P. 1742 - 1747

Published: Jan. 9, 2024

The proton-coupled electron transfer (PCET) mechanism for the reaction Mox–OH + e– H+ → Mred–OH2 was determined through kinetic resolution of independent (ET) and proton (PT) steps. interest triggered by visible light excitation [RuII(tpy)(bpy′)H2O]2+, RuII–OH2, where tpy is 2,2′:6′,2″-terpyridine bpy′ 4,4′-diaminopropylsilatrane-2,2′-bipyridine, anchored to In2O3:Sn (ITO) thin films in aqueous solutions. Interfacial kinetics PCET reduction were quantified nanosecond transient absorption spectroscopy as a function solution pH applied potential. Data acquired at = 5–10 revealed stepwise transfer–proton (ET–PT) mechanism, while measurements made below pKa(RuIII–OH/OH2) 1.3 used study analogous interfacial reaction, only mechanistic step. Analysis this data with recently reported multichannel model construct zone diagram supported assignment an ET–PT 5–10. Ultimately, represents unique example among Mox–OH/Mred–OH2 reactivity protonation oxidation states intermediate kinetically spectrally resolved firmly establish mechanism.

Language: Английский

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Photoelectrochemical Proton-Coupled Electron Transfer of TiO₂ Thin Films on Silicon

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(15), P. 10559 - 10572

Published: April 2, 2024

TiO2 thin films are often used as protective layers on semiconductors for applications in photovoltaics, molecule–semiconductor hybrid photoelectrodes, and more. Experiments reported here show that silicon electrochemically photoelectrochemically reduced buffered acetonitrile at potentials relevant to photoelectrocatalysis of CO2 reduction, N2 H2 evolution. On both n-type Si irradiated p-type Si, reduction is proton-coupled with a 1e–:1H+ stoichiometry, demonstrated by the Nernstian dependence Ti4+/3+ E1/2 buffer pKa. were conducted without illumination, photovoltage ∼0.6 V was observed across 20 orders magnitude proton activity. The 4 nm almost stoichiometrically under mild conditions. catalytically transfer protons electrons hydrogen atom acceptors, based cyclic voltammogram, bulk electrolysis, other mechanistic evidence. TiO2/Si thus has potential generate high-energy H carriers. Characterization after reveals restructuring formation islands, rendering potentially poor choice protecting or catalyst supports reducing protic Overall, this work demonstrates atomic layer deposition photoelectrodes undergo chemical morphological changes upon application only modestly negative RHE these media. While results should serve cautionary tale researchers aiming immobilize molecular monolayers "protective" metal oxides, robust electron reactivity introduces opportunities photoelectrochemical generation reactive charge-carrying mediators.

Language: Английский

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Efficient Decoupled Electrolytic Water Splitting in Acid through Pseudocapacitive TiO₂

Advanced Science, Journal Year: 2024, Volume and Issue: 11(28)

Published: May 14, 2024

Abstract Water electrolysis remains a key component in the societal transition to green energy. Membrane electrolyzers are state‐of‐the‐art technology for water electrolysis, relying on 80 °C operation highly alkaline electrolytes, which is undesirable many of myriad end‐use cases electrolytic splitting. Herein, an alternative process, decoupled described performed mild acidic conditions with excellent efficiencies. Decoupled sequentially performs oxygen evolution reaction (OER) and hydrogen (HER), at same catalyst. Here, H + ions generated from OER stored through pseudocapacitive (redox) charge storage, released drive HER. demonstrated using cheap, abundant, TiO 2 first time. To achieve acid ultra‐small anatase particles (4.5 nm diameter) prepared. These supported carbon felt electrode show electrochemical surface area capacitance 375 F g −1 . When these electrodes tested splitting overall energy efficiency 52.4% observed, stability over 3000 cycles testing. This can provide viable membrane electrolyzers—eliminating need electrolytes elevated temperatures.

Language: Английский

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Facilitating proton-coupled electron transfer for energy-efficient CO2 desorption by C@ZrO2 hollow composites

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: 495, P. 153332 - 153332

Published: June 19, 2024

Language: Английский

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Sulfur Migration Enhanced Proton-Coupled Electron Transfer for Efficient CO₂ Desorption with Core-Shelled C@Mn₃O₄

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(10), P. 4606 - 4616

Published: March 1, 2024

Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO

Language: Английский

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